Answer
$z=0$
Work Step by Step
$-5z+3z-7=8z-1-6$ $\longrightarrow$combine like terms
$-2z-7=8z-7$ $\longrightarrow$addition property
$-2z-7+2z+7=8z-7+2z+7$ $\longrightarrow$combine like terms
$0=10z$ $\longrightarrow$multiplication property
$0\div10=10z\div10$ $\longrightarrow$divide
$0=z$